Leviticus 13:13-17

then the priest shall look, and behold, if the leprosy has covered his entire body, he shall pronounce the one who has the infection clean; it has all turned white and he is clean.

But whenever raw flesh appears on him, he shall be unclean.

The priest shall look at the raw flesh, and he shall pronounce him unclean; the raw flesh is unclean, it is leprosy.

Or if the raw flesh turns back and is changed to white, then he shall come to the priest,

and the priest shall look at him, and behold, if the infected area has turned white, then the priest shall pronounce the one who has the infection clean; he is clean.